Check the earth connection(s) from the rear light clusters and on the clusters themselves particularly i fthese are based on a printed circuit board - these can develop cracked tracks.
X
July 2015
forgot to add that if a stop and tail bulb is changed ,it is fitted the right way [offset pins!]
k
July 2015
sounds like a wrong bulb fitted in rear light bulb board assy.check handbook for correct bulb/position
k
July 2015
I can answer this question...
52 mondeo brake light staying on only when lights are on?
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